Functional dissection of fibronectin type 3 domains of SORL1 in Alzheimers disease associated microglia

阿尔茨海默病SORL 1纤连蛋白3结构域的功能研究 疾病相关小胶质细胞 阿尔茨海默病（Alzheimer's disease，AD）是一种多因素的复杂疾病，是痴呆的主要病因之一 在老年人中。没有有效的预防药物， 由于缺乏对疾病机制的全面了解，有趣的是， 全基因组关联研究已经确定，大多数AD相关基因座是 在小胶质细胞（常驻巨噬细胞）中高度/独特表达的基因中或附近发现 提示这些细胞在疾病进展中的关键作用。SORL 1基因 与AD的迟发和早发形式有关。对死后脑组织的研究表明 降低AD患者大脑中SORL 1的水平。尽管在脑细胞中， SORL 1的最高表达，但很少有人知道这种蛋白质如何调节小胶质细胞表型 在健康和疾病期间。我们的初步数据表明，SORL 1的一种特殊亚型是 富含小胶质细胞，并通过其FN 3结构域与WAVE调节因子发生物理相互作用 复合物（WRC）。WRC正在成为细胞迁移和吞噬反应的关键调节因子 因此可以作为调节AD相关小胶质细胞表型的治疗靶点。在这 应用，我们提出：（1）确定SORL 1调节的分子机制 小胶质细胞功能，例如吞噬作用、趋化性和细胞因子表达;（2）测量SORL-1。 在AD和非AD脑小胶质细胞中的FN 3丰度， 个体（ROSMAP）以建立FN 3丰度与AD相关性状之间的关系; (3)使用我们新开发的CRISPR介导的 饱和诱变方法。 总的来说，通过利用创新的CRISPR-Cas9基因组编辑技术（1和3）和新的 基于SRM（selected reaction monitoring）的定量蛋白质组学和遗传学（2）该建议 将加速基因发现向分子机制的转变， AD的新疗法的途径。

Functional dissection of fibronectin type 3 domains of SORL1 in Alzheimer's disease associated microglia Alzheimer's disease (AD) is a multifactorial, complex disease and a leading cause of dementia among aged people. There are no effective pharmacotherapeutic options for prevention and treatment of AD due to lack of complete understanding of disease mechanisms. Interestingly, Genome wide association studies have established that the majority of AD associated loci are found in or near genes that are highly/uniquely expressed in microglia (resident macrophage cells of brain) suggesting the critical role of these cells in disease progression. SORL1 is genetically implicated in late and early onset forms of AD. Studies on postmortem brain tissues have shown reduced levels of SORL1 in AD patient brains. Although, among brain cells microglia show highest expression of SORL1, yet little is known how this protein regulates microglia phenotypes during health and disease. Our preliminary data suggest, that a specific isoform of SORL1 is enriched in microglia and it physically interact through its FN3 domain with WAVE regulator complex (WRC). WRC is emerging as critical regulator of cell migration and phagocytic response hence can serve as therapeutic target for tuning up phenotypes of AD related microglia. In this application, we propose to: (1) determine the molecular mechanism by which SORL1 regulate microglia functions e.g. phagocytosis, chemotaxis, and cytokine expression; (2) Measure SORL- FN3 abundance in AD and non-AD brain microglia from cohorts of deeply characterized individuals (ROSMAP) to establish the relationship among FN3 abundance vs. AD related traits; (3) Identify therapeutic targets within SORL1-WRC using our newly developed CRISPR-mediated saturating mutagenesis approach. Overall, by leveraging innovative CRISPR-Cas9 genome editing technologies (1 & 3) and novel SRM (selected reaction monitoring) based quantitative proteomics and genetics (2) this proposal will accelerate the transition of genetic discoveries to molecular mechanism that can open new avenues for novel therapeutics for AD.